Development of a High-Speed and Precision Micro- Spindle for Micro-Cutting

Wei Liu,Zhixiong Zhou,Xiangming Huang,Zhi-Jian He,Yong Du 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Mechanical micromachining using micro-machine tools is very competitive in manufacturing geometrically complex 3D micro-partsin various engineering materials with advantages of small space, energy-efficient, low equipment production and operation costs. Askey components of micro-machine tools, micro-spindles directly determine the performance of micro-machine tools and theapplication and development of mechanical micromachining technology. This study proposes a novel design concept of the separatelyspindle and tool and one-piece tool/rotor structure for micro-spindles, whose micro-tool can maintain good rotational accuracy athigh rotational speeds. In the principle prototype micro-spindle, an air driven turbine was used as power spindle. The design andoptimization of the micro-spindle were conducted. The fabrication and evaluation of the prototype micro-spindle were presented. Theresults of the principle prototype micro-spindle were analyzed and some efforts for the subsequent micro-spindle were proposed.

Observer-based Composite Adaptive Dynamic Terminal Sliding-mode Controller for Nonlinear Uncertain SISO Systems

Xiaofei Liu,Shengbo Qi,Reza Malekain,Zhixiong Li 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.1

In the present paper, the observer-based composite adaptive terminal sliding-mode control is investigatedfor the nonlinear uncertain system. First, an adaptive observer is designed to estimate the unavailable high-orderderivative of the output. Then, a new dynamic terminal sliding surface is proposed with a state filter, which aims todevelop the dynamic terminal sliding mode controller. By the composite adaptive control methods, a new adaptivelaw is designed, and the stability of the overall system is proofed based on the Lyapunov method. Finally, somenumerical simulations are conducted to validate the effectiveness of the proposed algorithm.

Characterization of the B cell receptor repertoire of patients with acute coronary syndrome

Weng Ruiqiang,Liu Sudong,Gu Xiaodong,Zhong Zhixiong 한국유전학회 2022 Genes & Genomics Vol.44 No.1

Background: Acute coronary syndrome (ACS) is a complex cardiovascular disease whose development involves the dysregulation of adaptive immune responses. Though it has been proven that T cells associate with inflammation in the development of ACS, the function of B cells in disease remains unclear. Objective: The aim of this study was to reveal the diversity of the B cell receptor (BCR) repertoire of patients with ACS. Methods: We conducted a pilot study to sequence the immune repertoire of peripheral blood mononuclear cells (PBMCs) from patients with ACS, including acute myocardial infarction (AMI) and unstable angina (UA), and quantitatively characterized BCR repertoires by bioinformatics analysis. Results: We found that patients with AMI and UA had lower BCR repertoire diversity compared with controls with normal coronary arteries (NCA). Lower percentages of productive unique BCR nt sequences and higher percentages of top 200 unique BCR sequences were identified in AMI and UA patients than NCA controls. Patients had various preferential usage of V and J genes from B cell clones in accordance with the disease severity of coronary arteries. AMI patients had distinct CDR3 amino acids, and their frequency differed among patients with ACS. Conclusions: Our results indicate that differential BCR signatures represent an imprint of distinct repertoires among ACS patients. This study thereby opens up the prospect of studying disease-relevant B cells to better understand and treat ACS.

Hydrogen sulfide ameliorates abdominal aorta coarctation-induced myocardial fibrosis by inhibiting pyroptosis through regulating eukaryotic translation initiation factor 2α phosphorylation and activating PI3K/AKT1 pathway

Yaling Li,Zhixiong Wu,Jiangping Hu,Gongli Liu,Hongming Hu,Fan Ouyang,Jun Yang The Korean Society of Pharmacology 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.4

This study aimed to assess the effects of exogenous hydrogen sulfide (H₂S) on abdominal aorta coarctation (AAC) induced myocardial fibrosis (MF) and autophagy in rats. Forty-four Sprague-Dawley rats were randomly divided into control group, AAC group, AAC + H₂S group, and H₂S control group. After a model of rats with AAC was built surgically, AAC + H₂S group and H₂S group were injected intraperitoneally with H₂S (100 µmol/kg) daily. The rats in the control group and the AAC group were injected with the same amount of PBS. We observed that H₂S can improve left ventricular function and the deposition of myocardial collagen fibers, inhibit pyroptosis, down-regulate the expression of P-eif2α in myocardial tissue, and inhibit cell autophagy by activating the phosphatidylinositol 3-kinase (PI3K)/AKT1 signaling pathway (p < 0.05). In addition, angiotensin II (1 µM) H9c2 cardiomyocytes were injured in vitro experiments, and it was also observed that pyroptosis was inhibited after H₂S (400 µmol/kg) intervention, the expression of P-eif2α in cardiomyocytes was significantly down-regulated, and the PI3K/AKT1 signaling pathway was activated at the same time. Therefore, increasing the expression of P-eif2α reverses the activation of the PI3K/AKT1 signaling pathway by H₂S. In conclusion, these findings suggest that exogenous H₂S can ameliorate MF in rats with AAC by inhibiting pyroptosis, and the mechanism may be associated with inhibiting the phosphorylation of eif2α and activating the PI3K/AKT1 signaling pathway to inhibit excessive cell autophagy.

Maternal undernutrition alters the skeletal muscle development and methylation of myogenic factors in goat offspring

Zhou Xiaoling,Yan Qiongxian,Liu Liling,Chen Genyuan,Tang Shaoxun,He Zhixiong,Tan Zhiliang 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.6

Objective: The effects of maternal undernutrition during midgestation on muscle fiber histology, myosin heavy chain (MyHC) expression, methylation modification of myogenic factors, and the mammalian target of rapamycin (mTOR) signaling pathway in the skeletal muscles of prenatal and postnatal goats were examined. Methods: Twenty-four pregnant goats were assigned to a control (100% of the nutrients requirement, n = 12) or a restricted group (60% of the nutrients requirement, n = 12) between 45 and 100 days of gestation. Descendants were harvested at day 100 of gestation and at day 90 after birth to collect the femoris muscle tissue. Results: Maternal undernutrition increased (p<0.05) the fiber area of the vastus muscle in the fetuses and enhanced (p<0.01) the proportions of MyHCI and MyHCIIA fibers in offspring, while the proportion of MyHCIIX fibers was decreased (p<0.01). DNA methylation at the +530 cytosine-guanine dinucleotide (CpG) site of the myogenic factor 5 (MYF5) promoter in restricted fetuses was increased (p<0.05), but the methylation of the MYF5 gene at the +274,280 CpG site and of the myogenic differentiation (MYOD) gene at the +252 CpG site in restricted kids was reduced (p<0.05). mTOR protein signals were downregulated (p<0.05) in the restricted offspring. Conclusion: Maternal undernutrition altered the muscle fiber type in offspring, but its relationship with methylation in the promoter regions of myogenic genes needs to be elucidated. Objective: The effects of maternal undernutrition during midgestation on muscle fiber histology, myosin heavy chain (MyHC) expression, methylation modification of myogenic factors, and the mammalian target of rapamycin (mTOR) signaling pathway in the skeletal muscles of prenatal and postnatal goats were examined.Methods: Twenty-four pregnant goats were assigned to a control (100% of the nutrients requirement, n = 12) or a restricted group (60% of the nutrients requirement, n = 12) between 45 and 100 days of gestation. Descendants were harvested at day 100 of gestation and at day 90 after birth to collect the femoris muscle tissue.Results: Maternal undernutrition increased (p<0.05) the fiber area of the vastus muscle in the fetuses and enhanced (p<0.01) the proportions of MyHCI and MyHCIIA fibers in offspring, while the proportion of MyHCIIX fibers was decreased (p<0.01). DNA methylation at the +530 cytosine-guanine dinucleotide (CpG) site of the myogenic factor 5 (MYF5) promoter in restricted fetuses was increased (p<0.05), but the methylation of the MYF5 gene at the +274,280 CpG site and of the myogenic differentiation (MYOD) gene at the +252 CpG site in restricted kids was reduced (p<0.05). mTOR protein signals were downregulated (p<0.05) in the restricted offspring.Conclusion: Maternal undernutrition altered the muscle fiber type in offspring, but its relationship with methylation in the promoter regions of myogenic genes needs to be elucidated.

Large-scale Field Tests of the Performance of Geogrid-reinforced Piled Embankment over Soft Soil

Gang Wang,Xianwei Zhang,Xinyu Liu,Zhixiong Chang,Zhihai Liu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

When constructing superstructures on soft soils, geogrid-reinforced embankments and pile-supported embankments are used widely to improve the soft foundation and prevent issues including excessive settlements and large lateral displacements, so it is crucial to understand and evaluate their performance systematically. This study focuses on a case of piled embankments for a motor-racing circuit under construction in China. Two large-scale field tests of pile-supported embankments with and without reinforcement were carried out to investigate the effect of geosynthetic reinforcement on the improvement of embankments. During long-term monitoring, instruments in the test sites measured earth pressures, settlements, lateral displacements, and pore water pressures, and the performances of the reinforced or unreinforced embankments were examined. Test results from the two test sites under similar loading are compared, and it is concluded that the geosynthetic-reinforcement considerably influences the improvement of load transfer and diminishment of total and differential settlements. The lateral restraint provided by the geogrids also reduced the lateral soil displacement and the influence of subsoil depth. The smaller excessive pore water pressures in the site with reinforcement were associated with the enhanced load transfer due to the geogrids. This study provides an important reference for the design and construction of this circuit and other related projects.

Caspofungin combined with hormones as preemptive therapy of chemotherapy-induced disseminated candidiasis in a patient

Yali, Liang,Zhichao, Qiu,Yaohe, Li,Anping, Liu,Zhixiong, Chen,Huliwen, Huliwen,man, Luo,jing, He,Xiaoyang, Xiaoyang,Hai, Lan Techno-Press 2021 Advances in nano research Vol.10 No.6

Disseminated candidiasis (DC) arising from nosocomial fungal infection is a life-threatening complication in critically ill, nonneutropenic patients. The overall nosocomial fungal infection rate in United States hospitals doubled from 1980-1990. Until recently, amphotericin B was the only agent available for the treatment of life-threatening candidal infections, but its use is plagued by toxicities including nephrotoxicity and infusion-related reactions such as rigors and hypotension. The availability of fluconazole, which is regarded more much less toxic than amphotericin B, prompted a surge in research to determine if it is as efficacious in the management of candidemia and hematogenously disseminated candidiasis. Complicating the interpretation of studies is the broad range of infection severity, from candidemia that may be transient and self-limiting to life-threatening hematogenously disseminated candidiasis. This study has used the models of Artificial neural network (ANN) and Support Vector regression (SVR) to accurately assess the clinical trials comparing fluconazole and amphotericin B demonstrate the efficacy of fluconazole for catheter-associated candidemia in critically ill patients when the likely pathogen is Candida albicans. As a result, Amphotericin B should remain the first-line agent for the management of candidemia and hematogenously disseminated candidiasis in all other patients. Also, SVR could accurately assess the efficacy of fluconazole for catheter-associated candidemia in critically ill patients.

Experimental study of reversal of multidrug resistance in human leukemia K562/DOX cells by toad venom

Hu, Pei,Qiu, Zhichao,Li, Yaohe,Liu, Anping,Chen, Zhixiong,Huliwen, Huliwen,Luo, Man,Guxuekui, Guxuekui,Xiaoyang, Xiaoyang,Xie, Ying,Lan, Hai Techno-Press 2021 Advances in nano research Vol.11 No.2

Acute leukemia is a malignant tumor originating from the hematopoietic system with the highest incidence and mortality. At present, the main clinical treatment of leukemia is still chemotherapy, during the course of which the multidrug resistance (MDR) will significantly reduce remission rate and disease-free survival rate of patients. MDR is the most important factor affecting refractory/recurrent acute leukemia. Therefore, reversing leukemia MDR is one of the best ways to improve the complete remission rate of refractory/recurrent acute leukemia, and the study of drugs and methods to overcome leukemia MDR has received extensive attention in the leukemia research field. This study was to primarily investigate the effects of Liushen pills on leukemia drug-resistant cell line K562/DOX in inhibiting growth, reversing resistance and inducing apoptosis in anticipation of providing useful cytological and molecular biological basis for the treatment of refractory/recurrent acute leukemia. The serum containing toad venom was prepared by means of Chinese drug serum pharmacology. MTT assay was used to detect the inhibitory rates of human leukemia cell line K562/DOX after being treated with the serum containing toad venom as well as daunorubicin, or with the serum containing toad venom alone at different time points. Real-time fluorescent quantitative analysis (RT-PCR) was performed to determine the effects of serum containing toad venom on the expression of BCL-2 mRNA in human leukemia cell line K562/DOX. Compared to the control group, toad venom showed inhibitory effects on K562/DOX cells; the expression level of BCL-2 mRNA in toad venom group were decreased, indicating that toad venom may reverse the resistance of K562/DOX cells by down-regulating the expression level of MDR1.

The Dual-frequency (20/40 kHz) Ultrasound Assisted Photocatalysis with the Active Carbon Fiber-loaded Fe³⁺-TiO₂ as Photocatalyst for Degradation of Organic Dye

Xiong, Shaofeng,Yin, Zhoulan,Zhou, Yuanjin,Peng, Xianzhong,Yan, Wenbin,Liu, Zhixiong,Zhang, Xiangyu Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Dual-frequency ultrasound assisted photocatalysis (DUAP) method was proposed to degrade a stable organic model effluent, cresol red (CR), using the prepared $Fe^{3+}$-doped $TiO_2$ with active carbon fiber loading ($Fe^{3+}-TiO_2/ACF$) as photocatalyst. The influence of key factors, including Fe doping amount and power density of dual-frequency ultrasounds (20/40 kHz), on the degradation efficiency was investigated. The degradation efficiency rises to 98.7% in 60 min accompanied by the color removal of CR liquid samples from yellow to colorless transparent at optimal conditions. A synergy index of 1.40 was yielded by comparison with single ultrasound assisted photocatalysis (SUAP) and the photocatalysis without ultrasound assisted (UV/$TiO_2$), indicating that a clear synergistic effect exists for the DUAP process. Obvious enhancement of degradation efficiency for the DUAP process should be attributed to production of large amount of free radicals by strong cavitational effects of dual ultrasounds.

The Dual-frequency (20/40 kHz) Ultrasound Assisted Photocatalysis with the Active Carbon Fiber-loaded Fe3+-TiO2 as Photocatalyst for Degradation of Organic Dye

Shaofeng Xiong,Zhoulan Yin,Yuanjin Zhou,Xianzhong Peng,Wenbin Yan,Zhixiong Liu,Xiangyu Zhang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Dual-frequency ultrasound assisted photocatalysis (DUAP) method was proposed to degrade a stable organic model effluent, cresol red (CR), using the prepared Fe3+-doped TiO2 with active carbon fiber loading (Fe3+- TiO2/ACF) as photocatalyst. The influence of key factors, including Fe doping amount and power density of dual-frequency ultrasounds (20/40 kHz), on the degradation efficiency was investigated. The degradation efficiency rises to 98.7% in 60 min accompanied by the color removal of CR liquid samples from yellow to colorless transparent at optimal conditions. A synergy index of 1.40 was yielded by comparison with single ultrasound assisted photocatalysis (SUAP) and the photocatalysis without ultrasound assisted (UV/TiO2), indicating that a clear synergistic effect exists for the DUAP process. Obvious enhancement of degradation efficiency for the DUAP process should be attributed to production of large amount of free radicals by strong cavitational effects of dual ultrasounds.